The Isotherms, Kinetics, and Thermodynamics of Acid Dye on Nylon6 with Different Amounts of Titania and Fiber Cross Sectional Shape

Abstract

The adsorption of acid dye on nylon6 yarns with different amounts of Titania (0.03% and 0.3% wt.) and the rate of adsorption with various fiber cross-sectional shapes (circular and triangular) were studied. According to results, dye adsorption rates in yarns increase by changing the cross-sectional shape from circular to triangular and by decreasing the amount of TiO2. The rates of dyeing were calculated at different temperatures, values of activation energy, standard affinities, entropies, and enthalpies. The results indicate that increasing the temperature leads to decreases in the values of partition ratio and affinity. Moreover, from the analysis of the thermodynamics of dyeing, the enthalpic and entropic terms were found to be negative. It was noted that the adsorption of acid dye on nylon6 was an exothermic process. The adsorption isotherm was tested by fitting the adsorption data with Langmuir, Freundlich, Redlich–Peterson, and Dubinin– Radushkevichisotherms. Result show that the adsorption isotherm of acid dye on nylon6 is Langmuir type.